The present invention relates to a method of temperature-calibrating a second heat treating apparatus based on a heat treatment result obtained by a first heat treating apparatus for reference in a semiconductor process. The term "semiconductor process" used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or an LCD (Liquid Crystal Display) substrate, by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
In the semiconductor process, a vertical heat treating apparatus is known as a batch type process apparatus that permits applying heat treatments such as a film forming process, an oxidizing process and a diffusion process to a number of semiconductor wafers at a time. The vertical heat treatment apparatus is used such that a number of wafers are arrayed and held with a gap therebetween in a vertical direction in a holder called a wafer boat, and then the holder is loaded into a vertical heat treating chamber and a heat treatment such as an oxidizing process is performed.
For subjecting a wafer to a heat treatment, it is necessary to control accurately the wafer temperature. For example, where an oxide film is formed on a wafer by an oxidizing process, the temperature of the wafer influences the thickness of the formed oxide film. Therefore, it is necessary to calibrate the temperature controller of the heater with a high accuracy.
Conventionally, a wafer equipped with a thermocouple is placed in a process chamber of a heat treating apparatus, in which the temperature is to be calibrated, so as to measure the wafer temperature and to perform the calibration on the basis of the measured value and the value indicated by a temperature controller. In a vertical heat treating apparatus disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 3-145121, the temperature control of the heat treating apparatus is performed on the basis of the relationship among the temperature of a wafer equipped with a thermocouple, the temperature within a process chamber, and the temperature of a heater. However, if the wafer equipped with the thermocouple is put in the heat treating chamber, the metals forming the thermocouple are scattered within the heat treating chamber so as to be attached to the heat treating chamber. The attached metals tend to be attached to a wafer to be processed (target wafer) so as to bring about contamination with the metals.
On the other hand, it is being studied to use in place of the thermocouple a radiation type thermometer, in which a radiant light radiated from a wafer is caught and is converted into an electric signal by a photoelectric element so as to measure the temperature of the wafer. In this case, the radiant light coming from portions other than the wafer is also incident on the light receiving section, thereby making it difficult to correct the thermal emissivity.